A systematic review of aerobic and resistance exercise and inflammatory markers in people with multiple sclerosis.

Inflammation is a driver in the demyelination process in patients with multiple sclerosis (MS) and can influence disability levels. Both single and repeated bouts of exercise can decrease inflammatory markers in people with MS (PwMS). This systematic review evaluates whether exercise can influence inflammation and disability in individuals with MS. Experimental studies were reviewed that had to meet the following eligibility requirements: a sample of PwMS, an intervention of exercise (either aerobic, resistance, or a combination of each), and an outcome that included at least one inflammatory (cytokine) reaction. The main outcome measure was an evaluation of inflammation, as indicated by a change in any cytokine level. Other measures included muscle strength, balance, flexibility, walking ability, disability statues, and quality of life (QOL). A total of nine studies were included in the final review. Exercise interventions included predominantly cycling, although a few resistance training trials were mentioned. Small decreases were found in IL-17 and IFN-γ after exercise. Functional outcome measures and perceived disability status were improved posttraining. We conclude that while interventions such as exercise may impact QOL, they do not have a significant influence on inflammation associated with MS. Exercise is an accessible alternative that not only helps to decrease impairments but also limit the restrictions associated with participation in society. While functional outcomes after exercise improved, these improvements may not be attributable to changes in levels of cytokines or inflammatory markers.